Sept. 18 (Bloomberg) -- European Union regulators are preparing an antitrust complaint over Microsoft Corp.’s failure to comply with a settlement to give users a choice of web browsers, according to two people familiar with the matter.

There’s no set timing for the European Commission to send the statement of objections, said the people who asked not to be identified because the complaint isn’t public.

A statement of objections lists alleged violations of competition rules and is a precursor to possible fines.

EU Competition Commissioner Joaquin Almunia said in July that Microsoft may have misled regulators by failing to display a browser choice screen to users of the Windows operating system since February 2011.

The world’s largest software company blamed a technical error for not showing the screen to some users and offered to extend until March 2016 a commitment to show it.

Microsoft has already been fined 1.68 billion euros ($2.2 billion) in EU antitrust probes, including an 899 million-euro penalty for failing to obey an order to share data with competitors.

The Redmond, Washington-based company agreed to offer access to rival browsers as a part of a 2009 settlement to repair its relationship with the bloc’s regulators. It told regulators last December that it was complying with its commitments.

Microsoft’s press office in Brussels declined to comment beyond a July statement in which the company expressed its regret that the error occurred and understood that regulators may penalize it.

Technical Error

The company said it only learned in July that it didn’t offer its browser choice software to some 28 million computers running Windows 7 Service Pack 1, or 10 percent of the computers that should have received it. It blamed a technical error and said it has already started distributing a fix.

The European Commission declined to comment.

Under the terms of Microsoft’s 2009 pledge, consumers who buy personal computers were given a choice of the 12 most widely used browsers to install in addition to, or instead of, Microsoft’s Internet Explorer.

Any fines for Microsoft may take into account repeat offenses, Almunia said in July in a reference to the EU’s 2008 penalty for the company’s failure to obey an earlier EU decision. That ruling also ordered it to provide information to software developers to make compatible products. EU antitrust fines are usually capped at 10 percent of yearly revenue.